The pressure sensor had been widely used to effectively monitor the flow status of the water distribution system for ensuring the reliable water supply to urban residents for providing the prompt response to potential issues such as burst and leakage. This study aims to present a method for evaluating the performance of pressure sensors in an existing water distribution system using transient data from a field pipeline system. The water distribution system in Y District, D Metropolitan City, was selected for this research. The pressure data was collected using low-accuracy pressure sensors, capturing two types of data: daily data with 1Hz and high-frequency recording data (200 Hz) according to specific transient events. The analysis of these data was grounded in the information theory, introducing entropy as a measure of the information content within the signal. This method makes it possible to evaluate the performance of pressure sensors, including identifying the most sensitive point from daily data and determining the possible errors in data collected from designated pressure sensors.

With the growth of silicon-based semiconductor sensors in the global sensor market, advancements in body motion detection for wearable devices and sustainable health monitoring have accelerated. This has led to a significant attention on various sensors with excellent flexibility and stretchability, such as PDMS, in numerous applications. In this study to adjust the sensitivity of conventional conductive pressure sensors, a porous sponge structure was initially created using a sugar template method. The polymer was prepared with four different ratios (5:1, 10:1, 20:1, 30:1) to achieve varying flexibilities. To ensure conductivity, the sponge was coated using a dip-coating method with a 3wt% CNT solution. The conductive sponges with various ratios were tested for sensitivity, demonstrating characteristics suitable for a wide range of pressure sensing applications.

The Climate chamber system is an essential facility for aerodynamic performance development of commercial vehicles to investigate air flow field characteristics in different climatic conditions. In particular, the analysis of airflow fields within the chamber system is an essential consideration for optimal design. In this study, the pressure characteristics and velocity uniformity in the test section area were predicted with blower impeller rotational speed using CFD. The velocity uniformity is affected by the distance from the blower nozzle outlet, reaching up to 72.7% at 695 RPM. The pressure differential between 300 RPM and 740 RPM shows an approximate difference of 2651 Pa, with a high-pressure distribution observed along the right side wall of the blower. These results are expected to be used as design data applicable for improving the performance of environmental chamber systems.

In this study, the characteristics of wind pressure distribution on circular retractable dome roofs with a low rise-to-span ratio were analyzed under various approaching flow conditions by obtaining and analyzing wind pressures under three different turbulent boundary layers. Compared to the results of previous studies with a rise-to-span ratio of 0.1, it was confirmed that a lower rise-to-span ratio increases the reattachment length of the separated approaching flow, thereby increasing the influence of negative pressure. Additionally, it was found that wind pressures varied significantly according to the characteristics of the turbulence intensity. Based on these experimental results, a model for peak net pressure coefficients for cladding design was proposed, considering variations in turbulence intensity and height.

As a safety device, a rupture disc are used to control pressure to minimize the explosion risk once the internal pressure of high pressure equipment exceeds a critical level. In this paper, optimization method was developed to secure optimal design of domed Rupture disks. The parameter analysis was performed through design of experiment to parameter of Rupture disk made of AISI 316.The Diameter, Thickness and Hight of Rupture disk were selected as design parameters for design parameter analysis. The results of parameter analysis revealed that the Diameter, thickness and hight were burst pressure-sensitive design parameters. Based on the valid performance factors, a regression equation to predict its performance was deducted and using the equation, an optimal design. And a sample model was fabricated, followed by burst pressure testing, after optimal design and analytical verification. In this research, it is verified that the optimal design method and the credibility of the analysis of this study is deemed very high. Furthermore, utilizing this mechanism would inspect the effect of the design parameter performance and increase the credibility and efficiency of a design.

The blockage rate for three kinds of nets commonly used in agricultural facilities was assessed by using the image acquisition and its relevant processing. By using both empirical relations presented by Idel’chik and Richards and Robinson, and the blockage rate obtained from the image processing, the pressure drop through the nets was predicted and also compared with wind tunnel experiment results. The results of the study showed that the blockage rate of the net was discriminated according to such factors as the magnitude of nets, the existence of inside threads, the thickness and number of threads. In addition, the blockage rate for the incident angle of 0° when the wind blew at the front had the range of 0.22－0.29 (0.22－0.32 when considering whole incident angles from 0° to 45° by 15°). For the nets with the blockage rate of about 30% or below, the prediction by the empirical relations of by Idel’chik and Richards and Robinson showed a little higher pressure drop overall than that of the wind tunnel test, but the use of the empirical relations and the blockage rate could be thought of as providing effectively meaningful guidelines for the safe design of agricultural facilities including nets because the wind tunnel test has been tedious and expensive. Further research and potential application on the prediction technique of the pressure drop, regarding both a subtle deformation by the wind and manufacturing methods with regard to the level of knots and the existence of inside threads, needs to be done for the nets with higher blockage rate.

The change in the performance of the range hood according to the pressure change was investigated through a comparative experiment, and the conclusion is as follows. KS C 9304: In 2020, static pressure was applied at 100 Pa according to the fan standard, and the test was conducted by varying the outlet diameter and power consumption. In the case of Motor power 55W, the air volume value was 184.6 when the outlet diameter was 125mm. As a result of the test, if the power consumption is 52.0W, the diameter of the outlet is 125mm, and the power consumption is 60.8W, and the diameter of the outlet is 100mm, it meets 160 or more and less than 200 (constant pressure 100Pa).

In this study, the structural integrity of the composite rocket motor case of a space launch vehicle was evaluated by conducting compression and bending tests. Two composite rocket motor case specimens with different stacking patterns were prepared for each test, and a dedicated jig was designed and manufactured. The test procedure was developed and applied separately for compression and bending tests. By performing these tests, the composite rocket motor case structural safety was assessed.

The influence of specimen geometry and notch on the hydrogen embrittlement of an SA372 steel for pressure vessels was investigated in this study. A slow strain-rate tensile (SSRT) test after the electrochemical hydrogen charging method was conducted on four types of tensile specimens with different directions, shapes (plate, round), and notches. The plate-type specimen showed a significant decrease in hydrogen embrittlement resistance owing to its large surface-to-volume ratio, compared to the round-type specimen. It is well established that most of the hydrogen distributes over the specimen surface when it is electrochemically charged. For the round-type specimens, the notched specimen showed increased hydrogen susceptibility compared with the unnotched one. A notch causes stress concentration and thus generates lots of dislocations in the locally deformed regions during the SSRT test. The solute hydrogen weakens the interactions between these dislocations by promoting the shielding effect of stress fields, which is called hydrogen-enhanced localized plasticity mechanisms. These results provide crucial insights into the relationship between specimen geometry and hydrogen embrittlement resistance.

Gate valves are hydraulic components used to shut-off the water flow in water distribution systems. Gate valves may fail owing to various aspects such as leakage through seats, wearing of packing, and corrosion. Because it is considerably challenging to detect valve malfunctioning until the operator identifies a significant fault, failure of the gate valve may lead to a severe accident event associated with water distribution systems. In this study, we proposed a methodology to diagnose the faults of gate valves. To measure the pressure difference across a gate valve, two pressure transducers were installed before and after the gate valve in a pilot-scaled water distribution system. The obtained time-series pressure difference data were analyzed using a machine learning algorithm to diagnose faults. The validation of whether the flow rate of the pipeline can be predicted based on the pressure difference between the upstream and downstream sides of the valve was also performed.

This study aims to measure sedimentation status change with the changes in internal pressure for dry chemical extinguishers of various use periods and analyze the suitability of the fire extinguishers' performance criteria. When the internal pressure of the fire extinguisher is 0%, 2 out of 10 new dry chemical powders for the 5 elapsed years were noted to be suitable, including 3 recycled dry chemical powders with 5 elapsed years that were found eligible. One out of 10 new dry chemical powders for 10 elapsed years was shown as suitable. Also, one new dry chemical powder for 13 elapsed years was suitable. When the internal pressure of the fire extinguisher was 50%, all 10 out of 10 new dry chemical powders for 5 years, recycled one with 5 elapsed years, and a new one with 10 elapsed years were found to be suitable, while 9 new dry chemical powders for 13 years were shown as suitable. When the internal pressure of the fire extinguisher was normal, new ones with 5 elapsed years, recycled ones with 5 elapsed years, new ones with 10 elapsed years, and new ones with 13 elapsed years were all 10 out of 10 samples noted as suitable. In summarizing the experiment results, it was found that the sedimentation status, one of the fire extinguisher's physical properties experiments, affects the fire extinguisher's performance criteria rather than the change with use periods.

Determination of explosion reference pressure is important in designing and testing flameproof enclosures (Ex d). Although relative humidity affects to explosion pressure, its effect is not well investigated for the gas group IIB, IIA, and I. This study tested explosion pressure for Ethylene (8 vol.%), Propane (4.6 vol.%), and Methane (9.8 vol.%), which are the representative gas of the gas group IIB, IIA, and I, at ambient temperature and atmospheric pressure (1 atm) under different relative humidity (0% ~ 80%). Ethylene- and Propane-air mixed gases generally tended to decrease as the relative humidity increased; however, explosion pressure was largely dropped at 20% of relative humidity compared to 0% and 10% of relative humidity. On the other hand, Methane-air mixture gas showed similar pressures at 0% and 10% of relative humidity; but no explosion occurred at more than 20%. The results of this study can be used in setting a testing protocol of explosion reference pressure for designing and testing a flameproof enclosure.

This study is a leading case of empirical analysis of whether, when corporate stakeholders (government, investors, customers, managers, employees) put pressure on companies for ESG management, it affects the introduction and implementation of ESG activities (environmental, social, governance) and affects business performance. As for the research method, a sustainability report was published, and a web survey of Korea Research Inc. was conducted from May 10 to May 20, 2022 targeting ESG management managers of 192 companies, and analyzed through the PLS structural equation model. As a result of the study, it was found that the introduction and execution of ESG is closely influenced by the pressure from the government, investors, managers, and employees, and in particular, the internal pressure of current managers and executives and employees has a great impact on the introduction and implementation of environmental, social, and governance activities. In particular, although external pressure also has some influence, it is practical to suggest that strong internal pressure is necessary for continuous activities and performance. And, methodologically, the main activity indicators of the GRI Reporting Guidelines, which are the most representative ESG management indicators, were developed as a questionnaire, and reliability, validity, and model fit were secured through comparison with indicators of multiple systems and expert reviews. The limitations of this study are that more in-depth analysis by industry or size is possible when ESG management is mature and sufficient samples are secured, and complex ESG pressure factor modeling is possible when more diverse stakeholders are added.

This paper presents a computational fluid dynamics (CFD) analysis to investiagate the effect of expansion chamber on overpressure reduction in protective tunnels subjected to detonation of high explosives. A commercial CFD code, Viper::Blast, was used to model the blast waves in a protective tunnel with a length of 160 m, width of 8.9 m and height of 7.2 m. Blast scenarios and simulation matrix were establihsed in consideration of the design parameters of expansion chamber, including the chamber lengths of 6.1 m to 12.1 m, widths of 10.7 m to 97 m, length to width ratios of 0.0 to 5.0, heights of 8.0 m and 14.9 m, and ratios of chamber to tunnel width of 1.2 to 10.9 m. A charge weight of TNT of 1000 kg was used. The mesh sizes of the numerical model of the protective tunnel were determined based on a mesh convergence study. A parametric study based on the simulation matrix was performed using the proposed CFD tunnel model and the optimized shape of expansion chamber of the considered tunnel was then proposed based on the numerical results. Design recommendations for the use of expansion chamber in protective tunnel under blast loads to reduce the internal overpressures were finally provided.

This study aims to explore the appropriate water pressure control of water supply pipeline to reduce water losses of water supply network in Jinan-gun. The current water pressure status of each 5 blocks and the impact of optimized water pressure on improving revenue water rate were investigated. In order to obtain the flow rate and water pressure data of each small block, a smart hub is set in the pressure reducing valve chamber at the inlet of the small block, and a smart water pressure meter is installed in the fire hydrant and the faucet of the customer. For the pressure reducing valves installed for water pressure management system of each block, the diameter calculation standard and type of the pressure reducing valve are determined, and the application reasons are put forward. The analysis results of water pressure management for each small block in Jinan-gun show that the pressure control equipment and water pressure management need to be improved in four small blocks. The water flow rate in Jinan-eup and Sangjeon-myeon increases from 57.2% to 87.6% when the water pressure control is completed.

Sensory evaluation of shucking pressure, pressure holding time, seeding method, difference in full shucking rate in the aquaculture area and shucking oyster was performed using an ultra-high pressure oyster shucking machine. The reaching time for each target pressure is 2.2-2.4 MPa/sec in the range of 180 MPa to 240 MPa. had a rate of pressure rise. There was a difference of 0.5-1.7℃ in the range of 24-27℃ in the seawater temperature before and after the pressure treatment inside the pressure vessel, but there was no specific increase or decrease in seawater temperature. When only the shucking pressure is increased without the pressure holding time, the critical shucking pressure at which the oyster shell is opened and the flesh is peeled in the range of 200 to 220 MPa. When the critical shucking pressure is reached, the oyster sample in the closed vessel is expected to be shucked by about 40%. If there is no pressure holding time when judged only by full shucking, an increase in pressure of about 1.5 MPa is required to further shuck 3% of the oyster population. The oyster samples cultivated in the south coast of Korea were subject to full shucking under the conditions of 220 MPa shucking pressure and two minutes (120 seconds) of pressure holding time, and the difference in the pressure of the oysters according to the oyster seeding method and the farming area was minute. Finally, the condition of 220 MPa of shucking pressure and three minutes of pressure holding time was the best at 1.52 when the result of the sensory evaluation performed manually was set to 1.0. Next was 1.4 under the conditions of 220 MPa of shucking pressure and one minute of pressure holding time (60 seconds), and 1.3 under the condition of 220 MPa and two minutes of pressure holding time (120 seconds). Therefore, it is considered that the most desirable shucking conditions, considering the efficiency and sensory evaluation results, are the conditions of 220 MPa shucking pressure and two to three minutes of pressure holding time.

In this study, a graphite block is fabricated using artificial graphite processing byproduct and phenolic resin as raw materials. Mechanical and electrical property changes are confirmed due to the preforming method. After fabricating preforms at 50, 100, and 150 MPa, CIP molding at 150 MPa is followed by heat treatment to prepare a graphite block. 150UP-CIP shows a 12.9% reduction in porosity compared with the 150 MPa preform. As the porosity is decreased, the bulk density, flexural strength, and shore hardness are increased by 14.9%, 102.4%, and 13.7%, respectively; and the deviation of density and electrical resistivity are decreased by 51.9% and 34.1%, respectively. Therefore, as the preforming pressure increases, the porosity decreases, and the electrical and mechanical properties improve.

This study was conducted to evaluate the filtration performance according to the feed temperature composed of NaCl and the operating pressure of the brackish water reverse osmosis (BWRO) process. The temperature is known that decides the filtration performance of reverse osmosis (RO). It is noted that temperature increase activates the permeate of salts due to augment of diffusivity and mass transfer. Filtration of the lab-scale RO system was performed with constant pressure and the constant flow was simulated. The salt rejection measured by the concentration of the feed and permeate was compared with water permeability and salt permeability in the conditions containing various temperatures (5, 10, 15, 20, 25, and 30℃) and pressures (10, 12, 15, and 18 bar). An increase in feed temperature from 5 °C to 30 °C caused a 4.65% decrease in salt rejection in CSM, due to an increase in salt permeability (4.06 times) rather than an increase in water permeability (2.62 times). Specific energy consumption (SEC) was calculated by using an electricity meter set in the RO system. It was expected that the SEC by the increases in temperature and pressure decreased due to the viscosity decline of the feed and the permeate flux augment, respectively. The SEC decreased by 63.4% in CSM and by 54.3% in Nittodenko when the feed temperature increased from 5 °C to 30 °C. It discussed how to operate the optimal RO process through the effect of temperature and operating pressure and the comparison of SEC.